AND THOSE OF CERTAIN OTHER MAMMALIA. 97 



lobed, and by the Old-World monkeys of a bi-lobed placenta ; and 

 should Professor Breschet's anticipations prove to be correct, we 

 should have an additional, though slight confirmation of the law 

 which teaches us to expect to find considerable differences in 

 structure and in habits between Old- World animals and their 

 South- American representatives, and an additional, though slight 

 confirmation of the general value of the placental system from a 

 classificatory point of view. I call the confirmation it would lend 

 to these great principles but slight, firstly, because the anthropo- 

 morphous apes, if we may judge, at least, from one of them, viz. 

 the chimpanzee (Troglodytes nic/er), resemble the New- World 

 monkeys, and differ from the Old- World species, so much nearer 

 to them in other structures and in place, in possessing a uni-lobed 

 placenta ; and, secondly, because such a point as the divarication 

 of such an organ as a placenta, which is usually a single mass, into 

 two or more naked-eye masses, seems to me but of small mor- 

 phological importance. Such an example as that of the ferret 

 (Mustela furo), already detailed from Daubenton, deters one from 

 assigning any very great value to the continuity or discontinuity 

 of the cellulo-vascular mass, which it is not pretended has changed 

 its relations either to allantois, to amnios, or to umbilical vesicle. 

 The placenta of the Leporidae will not, I anticipate, be found to be 

 uniformly bi-lobular or multi-lobular ; and a reference to any work 

 on midwifery 1 will show that very great varieties of the like nature 

 may exist in the placenta of our own species. 



It would, however, be highly interesting to have further obser- 

 vations made as to the placentae of the long-nosed monkey (Semno- 

 pithecus nasicus) amongst the lower 01d-W r orld Simiadae, and of the 

 Cattithrix sciureus amongst the New- World monkeys, as in speci- 

 mens of their placental structures (which were, however, in loth cases 

 alike in a lad state of preservation) Professor Breschet 2 was 

 unable to satisfy himself that his rule held good. 



1 Cazeau, 1. c. p. 191, where a figure of a cotyledonary human placenta is given. 



2 Professor Breschet's words are (I.e. p. 461), 'S'il ne s'est glisse" aucune erreur 

 dans l'histoire du fait anatomique, il faut avouer que la loi que j'dtablissais de 

 l'existence d'un double placenta dans l'oeuf des Singes de l'ancien continent, et d'un 

 seul placenta dans celui des Singes d'Ame'rique, n'est pas exacte ou qu'elle soufire 

 des exceptions. Le mieux serait peutetre d'attendre que de nouvelles observations 



: vinssent eclaircir la question et lever tous les doutes sur le point. ' The following 

 account, therefore, which may apply, perhaps, to Professor Breschet's labours, will 

 nevertheless, I apprehend, give an incorrect impression of what his opinions are: 



H 



